About 40 dogs have gone missing in Magic Valley, Idaho, since November, according to the Humane Society of the United States, and worried pet owners don’t have any leads.

"Someone is coming around and plucking animals out of people's yards," Lisa Kauffman, Idaho director of the HSUS, told USA Today. "Two purebred collies were stolen this morning. We don't have any leads."

Dogs have been unhooked from chains, removed from fenced-in yards and, in one case, taken from crates inside a garage. Some witnesses have even reported seeing dogs lured into vehicles.

“They saw them loading them in their vehicle,” Debbie Blackwood, director of the Twin Falls Animal Shelter, told local NBC affiliate KPVI. “They let their little dog out, and next thing she knows a red van pulls up and she has to race out and retrieve it. Another person said a black Eldorado-type car. They caught the person calling their dog over to them."

Blackwood suspects the dogs are being taken as part of an illegal dog-fighting ring. Earlier this month, hikers found the body of German shepherd with its skull crushed along the north rim of the Snake River Canyon.

“There have been some found with mouth duct-taped shut and then their teeth had been filed off before that so they couldn’t fight back and were used to train dogs as bait dogs," Blackwood said.

The HSUS is offering a $5,000 reward for information, but although Craigslist is full of missing-pet posts and social media is buzzing about the dogs, the problem is difficult to track because many people don’t go to the police.

"We are trying to tell people to fill out police reports and make this official," Blackwood said.

The missing dogs are all different ages, sizes and breeds — everything from Great Danes to Chihuahuas, according to Craigslist posts.

Some residents say the problem is worse than authorities realize. According to one Craigslist post, more than 30 dogs have been stolen from yards just since Feb. 1.

“PLEASE file a report with the police,” the post reads. “Yes, they might not be able to do anything, but there needs to be a record of all of these missing and stolen dogs so they can see what we see ... an ALARMING increase in the number of dogs disappearing right out of backyards, out of dog runs, off of chains, etc. Something very, very wrong is going on here.”